how hard is it to either find a instrument cluster with a tach and temp gauge and just throw it in, or add those items in myself with aftermarket gauges?

I'm subscribing to this thread because I'd like to know if its a 'plug & play" swap for plain RS gauge clusters & analog Z24 clusters.

Well being my 85 is nothing dash wise like just a speedo,fuel, and lots of dummy lights here we go.I know that cars that came equipped with the actual gauges would require a different sensor for like the water temp for sure being there are two diff style sensors offered for my car one with the light on dash and the other for the actual gauge.I would think it is possible that the wiring harness may have the wires for a tach just not hooked into the the dash gauges(I won't swear to this) being in most car harness the wiring is pretty much identical and certain wiring is not plugged into a plug to connect.As for the oil sensor mine is oil light only and is a specific part for just the dummy light,has a single wire going to it.I would have to do some research in my manuals of schematics to check and verify if in fact a dash with gauges versus without u could swap and obviously u have to change the water temp,oil sender and tie in the tach wire if its there.I am tired and not too much on reading schematics tonight but,will look to see if its possible.I will cary my manuals tomm and see if u could just change the dash and then have to just change ur two sensors above I listed to see if it would work.That's my take right now.